Spring pin



FIG. 1 is a perspective view of a spring pin showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a left-side view thereof;

FIG. 5 is a right-side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

Dashed lines are used solely for the purpose of illustrating parts of the invention that are not claimed, and form no part of the claimed design. 

CLAIM The ornamental design for a spring pin, as shown and described. 